Brush or collector for electrical machines.



S. SPARROW. BRUSH 0E COLLECTOR ECE ELECTRICAL MACHINES.

APPLIOATION FILED FEB. 23, 1909.

Patented May 31,1910.

UNITED STATES PATENT OFFICE.

SIMON SPARROW, OF ST. LOUIS, MISSOURI, ASSIGNOR TO WAGNER ELECTRIC MANU-FACTURING COMPANY, OF ST. LOUIS, IVIISSOURI, A CORPORATION OF MISSOURI.

BRUSH OR COLLECTOR FOR ELECTRICAL MACHINES.

Specification of Letters Patent.

Application 1ed February 23, 1909.

To all whom 'it 'may concern:

Be it known that I, SIMON Srannow, a citizen of the United States,residing at the city of St. Louis, in the State of Missouri, haveinvented a certain new and useful Brush or Collector for ElectricalMachines, of which the following is such a full, clear, and exactdescription as will enable any one skilled in the art to which itappertains to make and use the same, reference being had to theaccompanying drawings, forming part of this specification.

My invention relates generally to means employed for connectingconductors to the collecting members of electrical machines, but mo-reespecially to means for attaching conductors to carbon brushes. Themeans heretofore in use for this purpose have proven to beunsatisfactory for the reason that the coecient of expansion of the carbon is larger than that of the metals used for the connecting parts. Theresult of this is that, should the brush become hot, the screw or rivetby means of which the conductor is attached will be stretched and thecontact pressure under normal temperature conditions be thereby eitherreduced or destroyed. Plug or wedge connections are objectionable forsimilar reasons, since the hole in t-he brush into which they areinserted increases in size more rapidly under the influence of heat thanthe plug or wedge and consequently loosens the contact. Imperfectcontacts also tend to become more imperfect on account of the .oxidationof the parts by the electric current.

The object of my invention is to provide connecting means which shall belight, give large area of contact, and be adapted to maintain apermanent contact regardless of the expansion or contraction of theparts due to changes in temperature.

In the accompanying drawings which illustrate my invention, Figure 1shows a brush partly in section provided with a cylindrical hole; Fig. 2is a perspective view showing a spring wound on a mandrel preparatory toplacing it in position; Fig. 3 shows a method of inserting the springinto the conducting cable and then into the brush; Fig. 4 is an enlargedvertical section of the brush and connecting parts; Fig. 5 is anisometric projection of the brush with the conductor attached inaccordance with my invention.

will be apparent that the spring when in the Patented May 31, 1910.

serial No. 479,466.

In the drawings 2 is a collecting member or brush which may be made ofcarbon or any other suitable material and may be of any desired shape. Acavity or aperture 5 of any suitable shape, but preferably cylin drical,is formed on any convenient part of the collecting member and may extendentirely through it if desired. A resilient member 3,preferablya helicalspring, placed in this cavity together with the conductor l, holds theconductor in contact with the collecting member. The conductor l may beof any suitable construction such as woven, or twisted, or simply an.aggregation of separate conductors. In the method of applying myinvention, which is shown in the drawings, I Wind the spring 3 on amandrel 4 and holding it under tension insert it into a tubular webconducting cable l and then into the cylindrical cavity 5 in thecollecting member, as shown in Fig. 9.. The spring is then released andthe mandrel withdrawn. The cable is thus elastically held in intimateand extended contact with the brush. It

position described will carry no appreciable current and will thereforenot be heated suiiiciently to destroy its elasticity. By thisconstruction I overcome the objections to the methods now in use formaking such connections. The spring always adjusts itself to thevariations in the size of the hole in the brush and thereby maintainsperfect contact. It is light and therefore does not materially increasethe inertia of the brush. It is easily placed in position without anydanger of breaking the carbon and is inexpensive. My device also has afurther advantage in that the connecting cable can be made to extendfrom the top rather than the side of the brush, thus economizing spaceon the commutator when desired.

Having fully described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is l. In a brush fordynamo-electric machines, the combination with a collecting memberprovided with a cavity, of a resilient member under compression situatedin said cavity, and a conductor lying between said resilient member andthe wall of said cavity.

2. In a brush for dynamo-electric machines, the combination with acollecting member provided with a cavity, of a spring 11 undercompression situated in said cavity, and a conductor lying between saidspring and the wall of said cavity.

3. In a brush for dynamo-electric machines, the combination with a.collecting member provided with a Cylindrical cavity, of a spring undercompression situated in said cavity, and a exble conductor lying betweensaid spring and the wall of said 10 cavity.

4f. A carbon brush, having a cylindrical

